The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 17, 1998
Filed:
Nov. 21, 1996
Sadao Kokubu, Aichi, JP;
Hisashi Aoki, Aichi, JP;
Takashi Mizuno, Aichi, JP;
Shinichi Koga, Aichi, JP;
Abstract
The invention relates to a transmission-reception system. A transponder receiver unit contained in the key bow of an ignition key has a power circuit that receivers, rectifies and smoothes the carrier wave signal transmitted together with a time reference signal and an enquiry signal from the transmission-reception ECU of a motor vehicle. A microcomputer in the transponder becomes active when the output voltage of the power circuit reaches a predetermined level or higher. When activated, the microcomputer measures the time length of the received reference time signal using the clock signal generated by an oscillation circuit, and calculates a ratio, as a correction coefficient, between the measured time length and a stored reference time value. The microcomputer decodes the enquiry signal while correcting the time information included in the time series pulse signal forming the enquiry signal, using the correction coefficient.